75 research outputs found
A Comparative Study of EU and US Trade Policies for Developing Countries: The Case of Agri-Food Products
No full textTrade relations between developed and developing countries are one of the hot topics of the ongoing World Trade Organization (WTO) negotiations. The conclusion of the Cotonou Agreement between EU and African, Caribbean and Pacific countries, the introduction of the EU’s Everything But Arms initiative for the least developed countries and the United States’ African Growth and Opportunity Act for 39 African Countries, represents tangible incentives for many developing countries to continue their efforts to open their economies and build free markets. This paper analyzes the trade creating effects of EU and US trade policies as total effect, for agri-food products of developing countries in a gravity model framework. Data refer to a 10 year period: 1996-2005. The findings show larger trade creating effects of EU trade policies, especially for upper-middle income countries. Variation in trade creation, across the years, is not statistically significant, except for the low-income countries.Gross Trade Creation, Agricultural Trade Policy, Developed and Developing Countries, International Relations/Trade,
Receptor-mediated endocytosis in plants
No full textIntroducing the concept of receptor-mediated endocytosis (RME) has completely changed the traditional view of endocytosis as a process by which cells simply transport molecules from the plasma membrane (PM) and extracellular space. Internalization of molecules by means of specific cell-surface receptors led to the notion that endocytosis is the master organizer of cellular signalling. RME spatially regulates the signalling outputs of PM receptors by either targeting them for degradation or relocating them to signalling endosomes. Recent studies revealed highly conserved mechanisms behind RME in all eukaryotes, including plants, demonstrating a major role of clathrin as well as post-translational modifications (PTMs) of PM receptors, such as ubiquitination and phosphorylation.
In this chapter, we will review the latest data on RME in plants and its function in regulating receptor-mediated signalling. While these recent developments contributed to a better understanding of RME in plants, further work is needed to precisely describe the molecular machinery and to resolve the signalling role of receptor pools localized to different endomembrane compartments
In vivo imaging of brassinosteroid endocytosis in Arabidopsis
No full textIncreasing evidence shows the involvement of endocytosis in specific signaling outputs in plants. To better understand the interplay between endocytosis and signaling in plant systems, more ligand-receptor pairs need to be identified and characterized. Crucial for the advancement of this research is also the development of imaging techniques that allow the visualization of endosome-associated signaling events at a high spatiotemporal resolution. This requires the establishment of tools to track ligands and their receptors by fluorescence microscopy in living cells. The brassinosteroid (BR) signaling pathway has been among the first systems to be characterized with respect to its connection with endocytic trafficking, owning to the fact that a fluorescent version of BR, Alexa Fluor 647-castasterone (AFCS) has been generated. AFCS and the fluorescently tagged BR receptor, BR INSENSITIVE1 (BRI1) have been used for the specific detection of BRI1-AFCS endocytosis and for the delineation of their endocytic route as being clathrin-mediated. AFCS was successfully applied in functional studies in which pharmacological rerouting of the BRI1-BR complex was shown to have an impact on signaling. Here we provide a method for the visualization of endocytosis of plant receptors in living cells. The method was used to track endocytosis of BRI1-BR complexes in Arabidopsis epidermal root meristem cells by using fluorescent BRs. Pulse-chase experiments combined with quantitative confocal microscopy were used to determine the internalization rates of BRs. This method is well suited to measure the internalization of other plant receptors if fluorescent ligands are available
PP2A phosphatases: the 'on-off' regulatory switches of brassinosteroid signaling
No full textInactivation of ligand-bound plasma membrane receptors is crucial for the regulation of their signaling outputs. The internalization of activated receptors and their subsequent targeting for recycling or degradation is controlled by posttranslational modifications, of which phosphorylation and dephosphorylation play an important role. Recent work suggests that a similar mechanism acts on the brassinosteroid (BR) receptor BR INSENSITIVE 1 (BRI1) in Arabidopsis thaliana to switch off BR signaling. The degradation of BRI1 requires a protein phosphatase 2A (PP2A)-mediated dephosphorylation that is specified by methylation of the phosphatase by a leucine carboxylmethyltransferase on membranes. PP2A is also reported to act positively on BR signaling by targeting the transcription factor BRASSINAZOLE-RESISTANT 1 (BZR1), a component downstream of BRI1. Thus, PP2A proteins play a dual role in the regulation of the BR pathway to switch between inhibition and activation of the BR signaling, depending on their substrate specificity and localization
Search for a CP-odd Higgs boson decaying to Zh in pp collisions at root s=8 TeV with the ATLAS detector
No full textSee paper for full list of authors – 13 pages plus author list + cover pages (30 pages total), 5 figures, 2 tables, submitted to Phys. Lett. B, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2013-06/International audienceA search for a heavy, CP-odd Higgs boson, , decaying into a boson and a 125 GeV Higgs boson, , with the ATLAS detector at the LHC is presented. The search uses proton--proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb. Decays of CP-even bosons to or pairs with the boson decaying to electron or muon pairs are considered, as well as decays with the boson decaying to neutrinos. No evidence for the production of an boson in these channels is found and the 95% confidence level upper limits derived for \sigma (gg\rightarrow A) \times \mbox{BR}(A \rightarrow Zh) \times \mbox{BR}(h \rightarrow f\bar{f}) are 0.098--0.013 pb for and 0.57--0.014 pb for in a range of 220--1000 GeV. The results are combined and interpreted in the context of two-Higgs doublet models
Search for W ' -> t(b)over-bar in the lepton plus jets final state in proton-proton collisions at a centre-of-mass energy of root s=8 TeV with the ATLAS detector
No full textA search for new charged massive gauge bosons, called W', is performed with the ATLAS detector at the LHC, in proton-proton collisions at a centre-of-mass energy of root s = 8 TeV, using a dataset corresponding to an integrated luminosity of 20.3 fb(-1). This analysis searches for W' bosons in the W' -> t (b) over tilde decay channel in final states with electrons or muons, using a multivariate method based on boosted decision trees. The search covers masses between 0.5 and 3.0 TeV, for right-handed or left-handed W' bosons. No significant deviation from the Standard Model expectation is observed and limits are set on the W' -> t (b) over bar cross-section times branching ratio and on the W'-boson effective couplings as a function of the W'-boson mass using the CLs procedure. For a left-handed (right-handed) W' boson, masses below 1.70 (1.92) TeV are excluded at 95% confidence level.ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1016/j.physletb.2015.02.051</p
Dynamics of isolated-photon plus jet production in pp collisions at √s=7 TeV with the ATLAS detector
No full textThe dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb−1. Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle
Dynamics of isolated-photon plus jet production in pp collisions at (√s)=7 TeV with the ATLAS detector
No full textThe dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb−1. Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon--jet invariant mass and the scattering angle in the photon--jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle. The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb^-^1. Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon-jet invariant mass and the scattering angle in the photon-jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle
A novel endosomal sorting complex required for transport (ESCRT) component in Arabidopsis thaliana controls cell expansion and development
No full textBackground: ESCRT mediates membrane remodeling in cellular processes such as endosomal sorting. The ATPase SKD1/VPS4 is essential for ESCRT function. Results: PROS is a plant-specific ESCRT component that increases SKD1/VPS4 ATPase activity and is required for cell expansion. Conclusion: Plants have evolved specific ESCRT components that are required for normal development. Significance: Diversification of ESCRT components in eukaryotes may provide additional regulatory mechanisms for ESCRT-dependent processes.
ESCRT proteins mediate membrane remodeling and scission events and are essential for endosomal sorting of plasma membrane proteins for degradation. We have identified a novel, plant-specific ESCRT component called PROS (POSITIVE REGULATOR OF SKD1) in Arabidopsis thaliana. PROS has a strong positive effect on the in vitro ATPase activity of SKD1 (also known as Vacuolar Protein Sorting 4 or VPS4), a critical component required for ESCRT-III disassembly and endosomal vesiculation. PROS interacts with both SKD1 and the SKD1-positive regulator LIP5/VTA1. We have identified a putative MIM domain within PROS that mediate the interaction with the MIT domain of SKD1. Interestingly, whereas MIM domains are commonly found at the C terminus of ESCRT-III subunits, the PROS MIM domain is internal. The heterologous expression of PROS in yeast mutant cells lacking Vta1p partially rescues endosomal sorting defects. PROS is expressed in most tissues and cells types in Arabidopsis thaliana. Silencing of PROS leads to reduced cell expansion and abnormal organ growth
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